Dear EC2 Customer,
You recently reached a limit on the volume of email you were able to send out of SMTP port 25 on your instance:
Instance ID: i-9b8924ce
* IP Address: 1.2.3.4
* Start date: 2011-06-01 22:47 +0000
In order to maintain the quality of EC2 addresses for sending email, we enforce default limits on the amount of email that can be sent from EC2 accounts. If you wish to send larger amounts of email from EC2, you can apply to have these limits removed from your account by filling out our online request form.
If you are unaware of your instance having sent emails, we advise checking your instance application(s) to confirm that this activity was intended. It is your responsibility to ensure that your instances and all applications are secured against unauthorized use. For suggestions on securing your instances, visit aws.amazon.com/security.
Regards,
Your Amazon Web Services EC2 team